а)( 1 - 3/4)* ( 4/5 - 3/4) б) 1/6 * 2/5 + 3/5 * 1/9  в)14 * ( 1/2 + 1/3 + 3/4)   г) 1/3 * 6/7 -1/7 * 3/4 . памагите поже.

а)(4/4-3/4)*(16-15/20)=1/4*1/20=1/80б)2/30+3/45=2/15в)14*(6+4+3)/12=14*13/12=91/6г)6/21-3/28=5/28